to increase quickly; to give sb a lot of sth to do, carry, etc.
to increase quickly
The weight just piled on while I was abroad.
pile sth on (to) sb
to give sb a lot of sth to do, carry, etc.
He felt his boss was piling too much work on him.
pile sth on
to make sth increase rapidly
The team piled on the points in the first half of the game.
pile sth on
to express a feeling in a much stronger way than is necessary
Don't pile on the drama!
pile sth on
to give sb more or too much of sth
The German team piled on the pressure in the last 15 minutes.
Definitions from the Oxford Advanced Learner's Dictionary, 9th edition